From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Colin Cross <ccross@google.com>
Cc: "Sumit Semwal" <sumit.semwal@linaro.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
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Subject: Re: [PATCH v5 2/2] mm: add a field to store names for private anonymous memory
Date: Fri, 21 Aug 2020 01:15:49 +0300 [thread overview]
Message-ID: <20200820221549.GV2074@grain> (raw)
In-Reply-To: <CAMbhsRRSHBbKTAu6iUf8YmdveOb9CVGsS+sRq6xjZ+uCFOk73A@mail.gmail.com>
On Thu, Aug 20, 2020 at 02:45:27PM -0700, Colin Cross wrote:
> >
> > Guys, could you please enlighen me, I don't understand -- we pass some
> > random user-space pointer and save it in vm_area_struct then in procfs
> > we treat it as "string" and print out? What prevents me to put some crap
> > here then unmap this pointer the kernel will cause page fault in procfs
> > output (in best scenario)?
>
> This is the same pattern used for /proc/pid/cmdline.
> acccess_remote_vm handles addresses in unmapped pages, it will return
> 0 if no bytes were readable.
Yes, been in this part of code too long ago, managed to forget. You know
I'm wondering do we really need a human readable names here? Maybe it would
be more convenient to keep say u64 number instead? This would eliminate
need to access VM at all. From user space point of view there should be
no difference how to recognize such VMAs (by name or by some ID). Or there
some need for string solely?
next prev parent reply other threads:[~2020-08-20 22:15 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 14:16 [PATCH v5 0/2] Anonymous VMA naming patches Sumit Semwal
2020-08-19 14:16 ` [PATCH v5 1/2] mm: rearrange madvise code to allow for reuse Sumit Semwal
2020-08-19 14:16 ` [PATCH v5 2/2] mm: add a field to store names for private anonymous memory Sumit Semwal
2020-08-19 14:37 ` Michal Hocko
2020-08-19 15:02 ` Matthew Wilcox
2020-08-19 17:48 ` Sumit Semwal
2020-08-20 15:46 ` Oleg Nesterov
2020-08-19 17:14 ` kernel test robot
2020-08-19 17:42 ` kernel test robot
2020-08-20 7:58 ` Michal Hocko
2020-08-20 23:28 ` Colin Cross
2020-08-21 3:21 ` Sumit Semwal
2020-08-21 7:24 ` Michal Hocko
2020-08-21 7:53 ` Michal Hocko
2020-08-21 8:02 ` Sumit Semwal
2020-08-20 16:00 ` Oleg Nesterov
2020-08-20 21:15 ` Kees Cook
2020-08-21 3:15 ` Sumit Semwal
2020-08-21 3:14 ` Sumit Semwal
2020-08-20 21:40 ` Cyrill Gorcunov
2020-08-20 21:45 ` Colin Cross
2020-08-20 22:15 ` Cyrill Gorcunov [this message]
2020-08-20 23:51 ` Colin Cross
2020-08-21 7:05 ` Cyrill Gorcunov
2020-08-20 21:45 ` Dave Hansen
2020-08-20 21:59 ` Cyrill Gorcunov
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